Structural reinforcement of vehicle cavities is commonly achieved by molding polymeric carriers into specific shapes that reflect the contours of the cavity requiring reinforcement, and locating expandable foam materials onto certain surfaces of the carriers. Thus, each carrier must be customized to a particular shape which requires the formation and use of multiple molds and further requires injection molding processes that are both time-consuming and costly. Many carriers require overmolding or multi-shot injection molding in order be formed in the correct shape and with sufficient density for reinforcing purposes. In attempts to reduce the cost and effort associated with manufacture of the carriers, attempts have been made to provide expandable foam materials without the inclusion of a carrier, as structural foams. The benefit is that that the size and shape of the structural foam can be quickly modified and customized to any necessary shape. Unfortunately, without a carrier, the strength of the reinforcement member that includes only the structural foam is reduced. Further, without a carrier it is difficult to control the expansion of the structural foam. It is thus desirable to provide a reinforcing structure that has the customization benefits of a structural foam alone, but still provides the requisite strength for cavity reinforcement. It is further desirable that the carrier add minimal weight and cost to the resulting structure, but still provide improved strength and reinforcement ability than would be realized from either the structural foam or the carrier alone.